Neural mechanisms to exploit positional geometry for collision avoidance

Tanaka, Ryosuke; Clark, Damon A.

doi:10.1016/j.cub.2022.04.023

Cited by 28 publications

(23 citation statements)

References 103 publications

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“…4h ) and the A–P gradient from LPLC1 onto PLP219 (Extended Data Fig. 7 ) could regulate collision avoidance 29 . Thus, we propose that conversion of visual space coordinates into graded synaptic connectivity is a shared feature of VPN wiring.…”

Section: Synaptic Gradients Are a Common Wiring Motifmentioning

confidence: 99%

Synaptic gradients transform object location to action

Dombrovski

Peek

Park

et al. 2023

Nature

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To survive, animals must convert sensory information into appropriate behaviours1,2. Vision is a common sense for locating ethologically relevant stimuli and guiding motor responses3–5. How circuitry converts object location in retinal coordinates to movement direction in body coordinates remains largely unknown. Here we show through behaviour, physiology, anatomy and connectomics in Drosophila that visuomotor transformation occurs by conversion of topographic maps formed by the dendrites of feature-detecting visual projection neurons (VPNs)6,7 into synaptic weight gradients of VPN outputs onto central brain neurons. We demonstrate how this gradient motif transforms the anteroposterior location of a visual looming stimulus into the fly’s directional escape. Specifically, we discover that two neurons postsynaptic to a looming-responsive VPN type promote opposite takeoff directions. Opposite synaptic weight gradients onto these neurons from looming VPNs in different visual field regions convert localized looming threats into correctly oriented escapes. For a second looming-responsive VPN type, we demonstrate graded responses along the dorsoventral axis. We show that this synaptic gradient motif generalizes across all 20 primary VPN cell types and most often arises without VPN axon topography. Synaptic gradients may thus be a general mechanism for conveying spatial features of sensory information into directed motor outputs.

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Section: Synaptic Gradients Are a Common Wiring Motifmentioning

confidence: 99%

Synaptic gradients transform object location to action

Dombrovski

Peek

Park

et al. 2023

Nature

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“…Other studies have also shown brain-wide activity during walking but not during other behaviors ( Aimon et al, 2019 ; Schaffer et al, 2021 ; Brezovec et al, 2022 ). This difference may arise because adaptive locomotion—to avoid obstacles ( Tanaka and Clark, 2022 ), cross gaps ( Triphan et al, 2010 ), and court potential mates ( Coen et al, 2014 )—depends heavily on the brain’s descending signals. Thus, we hypothesize that, although a core set of command neurons can drive both walking and grooming, more DNs are additionally engaged during walking to allow for more flexible navigation in continuously changing and complex environments.…”

Section: Discussionmentioning

confidence: 99%

Descending neuron population dynamics during odor-evoked and spontaneous limb-dependent behaviors

Aymanns¹,

Chen²,

Ramdya³

2022

eLife

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Deciphering how the brain regulates motor circuits to control complex behaviors is an important, long-standing challenge in neuroscience. In the fly, Drosophila melanogaster, this is coordinated by a population of ~ 1100 descending neurons (DNs). Activating only a few DNs is known to be sufficient to drive complex behaviors like walking and grooming. However, what additional role the larger population of DNs plays during natural behaviors remains largely unknown. For example, they may modulate core behavioral commands or comprise parallel pathways that are engaged depending on sensory context. We evaluated these possibilities by recording populations of nearly 100 DNs in individual tethered flies while they generated limb-dependent behaviors, including walking and grooming. We found that the largest fraction of recorded DNs encode walking while fewer are active during head grooming and resting. A large fraction of walk-encoding DNs encode turning and far fewer weakly encode speed. Although odor context does not determine which behavior-encoding DNs are recruited, a few DNs encode odors rather than behaviors. Lastly, we illustrate how one can identify individual neurons from DN population recordings by using their spatial, functional, and morphological properties. These results set the stage for a comprehensive, population-level understanding of how the brain’s descending signals regulate complex motor actions.

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“…Each optic glomerulus receives input from all of the individual cells belonging to a single-cell type, resulting in a functional map in the central brain ( Klapoetke et al, 2022 ). Moreover, both stimulation and silencing experiments argue that at least some VPN classes strongly modulate specific visually guided behaviors ( Hindmarsh Sten et al, 2021 ; Tanaka and Clark, 2020 ; Tanaka and Clark, 2022 ). Finally, the visual tuning of VPN types is heterogeneous across the population, allowing us to explore how strategies for reliable visual encoding during self-motion vary across differently tuned populations.…”

Section: Introductionmentioning

confidence: 99%

Visual and motor signatures of locomotion dynamically shape a population code for feature detection in Drosophila

Turner

Krieger

Pang

et al. 2022

eLife

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Natural vision is dynamic: as an animal moves, its visual input changes dramatically. How can the visual system reliably extract local features from an input dominated by self-generated signals? In Drosophila, diverse local visual features are represented by a group of projection neurons with distinct tuning properties. Here we describe a connectome-based volumetric imaging strategy to measure visually evoked neural activity across this population. We show that local visual features are jointly represented across the population, and that a shared gain factor improves trial-to-trial coding fidelity. A subset of these neurons, tuned to small objects, is modulated by two independent signals associated with self-movement, a motor-related signal and a visual motion signal associated with rotation of the animal. These two inputs adjust the sensitivity of these feature detectors across the locomotor cycle, selectively reducing their gain during saccades and restoring it during intersaccadic intervals. This work reveals a strategy for reliable feature detection during locomotion.

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Neural mechanisms to exploit positional geometry for collision avoidance

Cited by 28 publications

References 103 publications

Synaptic gradients transform object location to action

Synaptic gradients transform object location to action

Descending neuron population dynamics during odor-evoked and spontaneous limb-dependent behaviors

Visual and motor signatures of locomotion dynamically shape a population code for feature detection in Drosophila

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